The invention lies in the field of communications technology. More specifically, the invention relates to a method for dealing with peripheral units reported defective in a communications system.
In communications systems, methods for automatic restarting are used for putting defective assemblies, circuits and terminals back into operation as quickly as possible by means of a start-up attempt in order to minimize any downtimes. Although it is not possible to eliminate severe hardware defects by such methods, they can be used for eliminating faults which are rectified after a restart of the unit affected. Such faults can be caused, for example, by maintenance and servicing work on the communications system. In the methods previously proposed, the peripheral units affected by a fault such as assemblies, circuits and terminals are locked for a certain time and then taken into service again. Following the restart, the units affected are subjected to intensive monitoring for a certain period of time. They are finally taken into service if no further fault occurs during this monitoring period. Otherwise; the peripheral unit is finally locked out. The locked period has the purpose of filtering out only the first fault in each case when similar faults occur in large numbers. The monitoring time ensures sufficient system stability after the restart. It is especially in the peripherals of switching banks that assemblies, line units and terminals are frequently locked out too early by the dependability system by the known methods for restarting.
The object of the invention is to provide a method of dealing with peripherals in a communications system that have been reported as defective which overcomes the above-noted deficiencies and disadvantages of the prior art devices and methods of this kind, and which allows for the fastest possible restarting of peripheral units which are temporarily defective in communications systems.
With the above and other objects in view there is provided, in accordance with the invention, a method of dealing with peripheral units reported as defective in a communications system, which comprises:
providing a repetition counter for counting a number of start-up attempts in a restarting procedure;
initiating a locked phase for temporarily taking a given peripheral unit out of service;
initiating a monitoring phase during which the peripheral is temporarily started up and tests for faults are performed;
upon determining that the peripheral is free from faults, finally placing the peripheral in service following the monitoring phase;
upon detecting a fault during the monitoring phase, comparing a count of the repetition counter with a given threshold value; and
if the count of the repetition counter exceeds the threshold value, finally taking the peripheral out of service;
if the count of the repetition counter does not exceed the threshold value, incrementing the repetition counter and transitioning the peripheral into the locked phase;
whereby a duration of the locked phase is dependent on the count of the repetition counter.
The novel method provides for considerable relief of engineering and maintenance due to the fact that the necessity of taking defective devices into service manually is reduced. The downtimes are also very short compared with manual startup attempts by a service center. One side-effect of the increased availability are the reduced numbers of subscriber complaints, for example because of failed terminals or line connections. Restarting by means of the method according to the invention is basically possible for all peripheral line units, assemblies, circuits and terminals. Furthermore, continuously defective peripheral units are detected by the fact that they are not starting up after the restart process has ended.
In accordance with an added feature of the invention, the repetition counter is initialized in the course of starting the restarting procedure.
In accordance with an additional feature of the invention, a plurality of peripheral units are allocated the following hierarchy levels:
a) line unit;
b) assembly;
c) circuit;
d) terminal.
For the duration of the locked phases within the hierarchy levels of line unit, assembly, circuit and terminal, separate hierarchy-level-specific time series are preferably used in each case. In some cases, however, it may be appropriate to normalize the duration of the locked phases and of the monitoring phases centrally for all peripheral units to be taken into service. This provides the advantage that no adaptation to special fault situations of individual devices or groups of devices is necessary since, within the maximum number of possible start-up attempts, a failed start-up attempt is followed by the next one.
In accordance with an advantageous embodiment of the method according to the invention, peripheral units are also taken into consideration which are locked when a fault statistics counter associated with a fault analysis device overflows. The fault statistics counter should then be reset after each final start-up. Coupling with fault statistics counters makes it possible to stem floods of reports in the event of faults in communications systems.
The restarting procedure can also be started on initiation of a routine test control which carries out background tests for regular checks of hardware functions, after negative test results. In addition, peripheral units can be taken into consideration which are locked directly by a central device administration.
In accordance with a concomitant feature of the invention, a check is made before the restarting procedure is started as to whether the peripheral units to be taken back into service are qualified for automatic restarting in any case. Thus, special assemblies can be excluded from the treatment by the method according to the invention inasmuch as this is necessary for management reasons. Furthermore, the end of the locked phase can be followed by a status check of the units to be taken back into service. If this check results in the status xe2x80x9clockedxe2x80x9d, the monitoring phase is initiated next. Otherwise, the peripheral units are finally taken out of service. Correspondingly, the end of the monitoring phase can also be followed by a status check. The peripheral units are then only taken into service again if they are in the xe2x80x9creadyxe2x80x9d state. Otherwise, they remain in the previous state and are deleted from an administration list.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for dealing with peripheral units reported as defective in a communications system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.